Hi rosebud,
First, you best not be outputting more than you're drinking or you'll find yourself in very deep shit pretty quickly. It's pretty easy to check, and your doc should be on top of that, but the rule of thumb is you should be urinating between 1 and 1.5 liters minimum in 24 hours. Any less than that and your kidneys are going to be in trouble. And when your kidneys go..........so do you.
With an ileo, you no longer have your colon in the game, and many times when patients are given an ileostomy for things like Crohn's, their terminal ileum and ileocecal valve may also have to be removed. Your terminal ileum is where 95% of your digestive bile is reabsorbed and recycled, as well as a small amount of water, and your ileocecal valve is what controls when your small bowel contents are released into your now nonexistent colon. Bottom line is the more small bowel you've had removed.........the harder it will be to hydrate. It's really that simple.
Without a colon and the ability to absorb water, you have to 'trick' the small bowel into absorbing it for you. You do that by drinking things with the proper ratio of sugar (glucose) and salt (sodium) to water. When the ratio is correct, water molecules will be dragged through the intestinal wall and you'll hydrate. If the ratio is wrong, it makes things worse. I've written about this a million times on here, so you can find all the details if you search..........or just go to the World Health Organization website and look at Oral Rehydration Solution (ORS) recipes to see what I'm talking about. Without a colon, we're pretty much just like people in third-world countries that suffer from chronic diarrhea from drinking bad water. Their colons are inflamed and thus cannot absorb water, so the ORS is given to them so they can hydrate through their small bowel until their colons heal and can absorb again.
You'll find drinks are grouped into three categories depending on their ratios of glucose and sodium to water. They are hypotonic, isotonic, and hypertonic. Hypotonic are drinks that don't have enough glucose or sodium per liter, isotonics are in the right ratio, and hypertonics have too much. Think of them like the three bears.........you want just right (i.e., isotonic). Hypotonic drinks are things like pure water or diet soda.......things lacking in sodium and/or glucose. Hypertonics are things like Coke or Pepsi, Gatorade, or orange juice, which all have way too much sugar and not enough sodium. Isotonics are ORS and similar products. Now the important part......if you drink hypotonic drinks.......like plain water or diet soda........you won't absorb any of it, and it will dilute the contents of your small bowel and wash that away before your small bowel can properly absorb the nutrients. If you drink hypertonic drinks....like a Coke or Sprite or apple juice......there's too much sugar in the mix. And when your small bowel senses too much sugar (or salt), it tries to correct it by dragging water from your cells into the small bowel to mix with what's there and get to the right ratio for it to be able to absorb. Normally, the water it pulled from your body to dilute the mix would simply be reabsorbed by your colon, and there'd be no issue. But without your colon, that water ends up in your bag, and you get even more dehydrated. Then you'll drink more, and the process just repeats, and before you know it, you're in the ER getting IV fluids. Again, the more small bowel you have.........the more you can get away with. But without a colon.........you have to adjust what you drink to make your small bowel do your colon's job too. Or you dehydrate or become malnourished.
That's a very quick explanation of a very in-depth subject, so I encourage you to dig into it deeper. Once you know how to properly hydrate, it simply won't be an issue. And being short-gutted.........I learned that very early on.
;O)